Tamper indicating closures are not entirely novel in the closure art and have assumed various forms. In most instances the tamper indicating feature is formed as an integral part of the closure and after the closure is applied to the container, a portion of the closure must be broken in order to remove the closure.
The molding of such closures is quite expensive from the viewpoint of the cost of molds, the tooling to make the molds and for that reason more economical systems are being considered. One system is a threaded closure having a tamper indicating band attached to its lower rim by a plurality of frangible connectors and the band seats in an annular area of the container neck with a series of lugs. The band must be removed in order for the closure to be rotated off the finish of the container. Such a system is disclosed in U.S. Pat. No. 3,980,195, issued on Sept. 14, 1976.
Another prior art system is illustrated in U.S. Pat. No. 4,454,955, issued June 19, 1984.
While the foregoing systems have had wide acceptance and success in the trade, they are only good with plastic, injection molded closures, and effective systems that would work equally well with a metal closure or plastic closure have not been available. Metal closures have typically been fixed in place on threaded necks of bottles by a shrink band that overlaps the closure and bead of the container finish. These require cutting the band in a horizontal area below the closure or in some cases the band has vertical lines of perforation that can be torn to permit removal of the band. They are either stretched before application or shrunk, such as with heat, after application. Special tools and handling systems are required in the capping line to apply the band.
Roll-on metal closures have been used where a lower frangible ring is crimped under the transfer bead of the container when the cap is formed around the threads. Such a system is illustrated in U.S Pat. No. 3,601,273, issued Aug. 24, 1971.